WHO first recognised extranodal NK/T-cell lymphoma (ENKTCL) in 2001, thanks to technical advances in anatomopathology and immunohistochemistry. It is divided into nasal and extranasal subgroups depending on the primary site. Primary isolated NK/T-cell lymphoma of the testis is rare. Typical recurrence sites of primary testicular NK/T-cell lymphoma are the gastrointestinal tract, lymph nodes, skin, spleen and central nervous system. Nasal relapses of a primary NK/T-cell lymphoma of the testis are very rare and according to our knowledge, no other case has been reported yet in the literature. The authors report the case of a 35-year-old Caucasian man relapsing twice in the nasal cavity 1 year after initial diagnosis and treatment of a primary isolated, stage IE, ENKTCL of the testis. We report the clinical and radiological presentation of the nasal relapses and the different modalities of treatment that were applied. Sinonasal relapses of an isolated primary NK/T-cell lymphoma of the testis are very rare. ENKTCL is a very aggressive entity, even at an early stage, therefore, requiring a multimodal treatment approach including chemotherapy and radiotherapy. New strategies to treat this disease are needed.